Sesamoiditis (Pain under the ball of the big toe)

Pain directly underneath where the big toe is attached to the foot can be very painful and cause you to avoid shifting your weight properly, leading to many other issues.  Or, even if you can shift your weight, it can be almost impossible to push-off to take you next step.  Some people complain that it feels as though a tiny rock is in their shoe while others need to employ a significant 'limp' to make it across the room.  So what caused this pain and are you going to be stuck with it?

Before you read any further, I recommend that you read our knowledgebase information on pronation as it provides a great overview of the mechanics of the foot and ankle which will help you understand this information better.  

A sesamoid bone is a tiny bone that sits within a tendon and acts to provide leverage for the muscle so that it can apply a greater force to a joint. In this case, the tendon is the flexor hallucis longus and the sesamoid sits underneath the ball of the foot.  This tendon travels underneath the arch, under the big toe and attaches toward the end of the big toe.  This muscle functions to flex or curl the big toe downward and helps during the 'push off' during walking, running and jumping.  There are basically a couple of ways you can develop sesamoiditis.  The first is plain old trauma.  You step wrong, push off and twist or stomp your foot down hard and you bruise or inflame your sesamoid bone.  The second way to injure the sesamoid is through poor mechanics.  When the leg swings forward to take a step, the foot turns in slightly, preparing to land on the outside edge of the heel.  Once the foot lands, your body weight shifts onto the foot and the arch falls gradually to adapt to the ground surface and absorb shock.  This is called pronation, and it is normal.  Pronation also involves some rotation of the long bones of the foot, the metatarsals.  In particular, the first metatarsal along the inside of the foot rotates inward and if it goes too far or too quickly, it will cause a splaying, or angling, of the joint between this first metatarsal and the big toe (this can lead to bunions, but that's a different topic!)  This abnormal action will cause the sesamoid to be pulled toward the second toe, creating trauma and pain.

Clinically, these are the two most common causes seen in the clinic for sesamoiditis, however, there are others.  Besides the usual culprits of recently changed training schedules, surfaces, distances and equipment (includes old, worn out shoes that do not have enough cushioning) you should be aware of recent foot injuries or arthritic changes that may have resulted in some stiffness as well as assessing any abnormal movements that are affecting the way you walk.  

I have seen several people with shoulder injuries who presented with sesamoiditis.  Walking is a reciprocal motion, meaning that as you step with your left foot forward, your right arm swings forward with it.  If you are limited in arm or shoulder movement, the opposite leg will move less and in an abnormal pattern as well, causing bruising, splaying and altered mechanics that can cause pain.  You might ask someone to watch you walk a hundred feet or so, maybe several times, and see if they notice one side moving differently than the other.  If so, this should raise a red flag for you to have an expert assess where the problem is and offer you ways to correct it.  In this case, treating only your foot will result in a poor outcome.